Friction bolster spring



' Nov. 5, 1940.

D. F. SPROUL FRICTION BOLSTER SPRING 2 Sheets-Sheet 1- v Filed March 18,1959 Nov. 5, 1940. QRSPROUL' "2320,1215

FRICTION BOLSTER SPRING Filed March 18, 1959 2 Sheets-Sheet 2 PatentedNov. 5, 1940 UNITED STATES PATENT OFFICE FRICTION BOLSTER SPRINGDelaware Application March 18, 1939,881'131 No. 262,654

14 Claims. (Cl- 267-9) This invention relates to friction units for usein bolster supporting spring assemblies for railway cars.

One of the objects of the invention is the provision of a new andimproved friction unit for spring assemblies that is provided with novelmeans for increasing frictional resistance to the compression of theassembly as the same is compressed.

Another object of the invention is the provision of a new and improvedfriction unit having load supporting springs associated therewith.

A further object of the invention is the provision of a new and improvedfriction unit having 18 hinged sections reacted on by load supportingsprings for resisting the relative movement of the sections during thecompression of the unit.

A still further object of the invention is the provision of a new andimproved friction unit that may be manufactured at reasonable expense,is easily assembled, efficient in operation and that may be substitutedfor one of the spring units of the conventional bolster supportinghelical spring assembly.

.25 Other and further objects and advantages of the invention willappear from the following description taken in connection with theaccompanying drawings in which Fig. 1 is a side elevation of a vehicletruck 80 showing the invention in position therein, with parts brokenaway;

Fig. 2 is a horizontal section of the unit on the line 2:2 of Fig. 3;

' Fig. 3 is a vertical section of the unit on the line 3-3 of Fig; 2;

Fig. 4 is a vertical section of the unit taken at right angles to thatshown in Fig. 3 on the line 4-.-4 of Fig. 3;

Fig.5 is a view similar to Fig. 3 but showing the unit in compressedposition;

Fig. 6 is a perspective view of one of the friction elements;

Fig. 7 is a perspective view of one of the con- :necting' links betweena pair of friction elements;

4'5 Fig. 8 is a perspective view of one of the friction elements takenfromv a different position from that shown in Fig. 6;

. Fig. 9 is a perspective view of one of the followers, with parts insection; and

'50 Fig. 10 me side elevation of one of the friction units.

In the construction of freight car trucks, it is common practice tosupport the bolster from the truck frame by means of an assembly ofheli- 5 .cal springs beneath each end of the bolster. But

since helical springs are freely acting, it has been proposed to providemeans for preventing harmonic vibration of the spring assembly. Thisharmonic vibration may be prevented by introducing friction mechanismfor resisting either the compression or expansion of the assembly. Thepresent invention has for its principal object the introduction offriction means into the bolster supporting spring assembly that isadapted to function as a load supporting member and as a means forcreating friction for resisting the compression of the unit with anincreasing frictional resistance as the compression increases.

Referring now to the drawings, the reference character Ill designates arailway truck having the side frame I I provided with a bolster openingl2 into which an end of a bolster I3 extends. The bolster is supportedby a spring assembly I 4 which rests on a spring plank I5 supported bythe lower chord N5 of the side frame II, as is usual in such .20constructions. Since the details of the truck constitute no part of thepresent invention, it is not thought necessary to further illustrate ordescribe the same further than to say that the friction spring-unit Hhas been substituted for one of the (2,5 conventional helical springs I4at each end of the bolster.

The friction spring-unit I1 is of substantially the same length anddiameter as the conventional bolster supporting helical spring and maybe sub- '30 stituted for any one of the helicals of the spring assembly.Each of these units comprises a cap member or upper follower l8 providedon its underside with a recess I!) which is in the form of a segment ofa sphere but slightly less than 3,135 hemisphere and for convenience ofdescription may be referred to as a segmental spherical recess. Thefollower is provided with an inwardly extending segmental flange 2| onits lower portion which limits the turning movement of the friction '0elements, as will presently appear. This flange fades out at oppositesides of the recess IS in a plane at right angles to the plane ofmovement of the friction elements, as shown in Fig. 4. The eliminationof portions of this flange is for the purpose of facilitating theassembly of the device.

A base member or lower follower 22 is positioned vertically beneath theupper follower I8 and is a duplicate of the upper follower. It isprovided with a substantially spherical recess 23 and an inwardlyextending segmental flange 24 corresponding to the recess l9 and flanges2| of the upper follower.

The recess l9 and the-recess 23 are preferably, though not necessarily,substantially hemispheri- 5 cal in that when the flange 2| rests on theflange 24, the recesses l9 and 23 constitute a spherical recess. Theinner surfaces of the recesses 19 and 23 constitute friction surfacesand when the flange 2i rests on the flange 24, the two friction surfacesare concentric, that is, they have a common center as at 25 in Fig. 5.It is to be understood that each of these recesses may be a segment of asphere less than a hemisphere.

Suitable means are provided for frictionally engaging these segmentalspherical surfaces and for resiliently resisting the movement of thefollowers toward each other. In the form of the device selected toillustrate one embodiment of the invention, two friction elements areprovided for each recess. These elements are arranged in pairs, onemember of each pair being in the upper recess and the other in thelower. The members of each pair are movable relative to each otherduring the operation of the device. As shown, the recess I9 is providedwith the friction elements 26 and 21 and the recess 23 is provided withthe friction elements 28 and 29. These friction elements are hollow andthe friction elements in each recess, when taken together, form asegment of a sphere which is materially less than a hemisphere. For thepurpose of description, however, each friction element may be regardedas a quadrant of a sphere and since they are substantially duplicates ofeach other, except that the .members of each pair are reversed, only oneneed be described.

Each quadrant is providedwith a curved outer wall 3|, Fig. 6, and a flator straight vertical inner wall 32, Fig. 8, having a flat frictionsurface 33 which is adapted to engage a corresponding friction surfaceon the adjacent quadrant, as shown more clearly in Fig. 4 of thedrawings. Each of the quadrants or friction elements is provided with'abearing 34, Fig. 8 the axis of which extends transversely to the fiatwall 32 and is slightly greater than a semi-circle. This bearing issupported by the wall 32 and a transverse web 30. It is located adjacentto one end of the wall 32 or supporting quadrant. A link 35 having thejournals 36 and 31 thereon, which are adapted to engage the bearings 34and 49 of the quadrants 26 and 28, respectively, and a similar linkhaving journals 36a and 31a engages corresponding bearings 34a. and 40aon the quadrants 21 and 29, re-

' In other words, the link 35 connects the pair of quadrants 26 and 28and a similar link 3511. connects the quadrants 21 and 29.

The journals 36 and 31 are adapted to be held in the bearings 34 and 40by any suitable means such as the set screws 38 and 39 which engage insuitable grooves 4| and 42, Fig. 5, arrangedin the same plane in thejournals 36 and 31, respectively.

These set screws engaging in the grooves beyond the equatorial plane ofthe journals not only prevent withdrawal of the journals from theirbearings but limit the rotation of those journals to the plane of thegrooves. The link 35a is connected in a similar manner.

Suitable resilient means are provided for resisting the compression ofthe unit and for returning the parts to normal position after release.ployed for this purpose.

As shown, the springs 43 and 44 are em- The spring 43 is between thepair of quadrants 26 and 28 and the spring 44 is between the pair ofquadrants 21 and 29, Fig. 4. In order that these springs shall be heldin operative position within the hollow quadrants, each of the quadrantsis provided with a curved recess 45, Fig. 4, and the spring has apositioning member 46 in each end thereof having a dome-shaped head 41that engages in the corresponding recess 45. The positioning member 46is provided with a stem 48, Fig. 4, that extends within the spring and aflange 49 against which the spring is adapted to seat. The recesses 45are preferably, though not necessarily, substantially in the diameter ofthe opposed pair of friction members, as indicated in Fig. 3, and areparallel to the links 35 and webs 30 when the unit is extended, as shownmore clearly in Fig. 3 of the drawings. By means of this arrangement,the friction between the quadrants and engaging walls of the sphericalrecess is at a minimum because if we regard the links 35 and 35a asfulcrums and the springs as the power, the leverage that is the distancethe power is from the fulcrum (the springs from the links) increases asthe springs are compressed, hence there is greater pressure of thequadrants on the friction surfaces of the recesses as the unit iscompressed.

In the operation of the device, when the unit is compressed, themovement is resisted by the springs but as the springs yield, thesegments of each pair are caused to rotate in opposite directions. Thespring forces the segments out into frictional contact with the interiorof the recesses or sockets and also forces the segments in each recessinto frictional contact with each other since the curved surfaces of thesocket act as wedge surfaces for forcing the-segments of each recessinwardly toward each other.

The parts are constructed so that the segments in each socket rotate inopposite directions thereby frictionally resisting the compression ofthe unit. It will be seen from a comparison of Figs. 3 and 5 that as thesprings 43 and 44 are compressed, each pair of quadrants is caused torotate toward each other and since they rotate about the journals 36 and31 which are eccentric to the curved inner surfaceof the recesses orsockets in the followers, the springs, which willremain perpendicular tothe plane of the flanges 2| and 24, will move outwardly from nectionwith the accompanying drawings, that the construction and operation ofmy device will be apparent to those skilled in the art and that changesin size, shape, proportion and details of construction may be madewithout departing from the spirit and scope of the appended claims.

I claim as my invention:

1. A spring-unit for use in a bolster supporting spring assemblycomprising a cap member, a base member, said members having opposedhemispherical recesses, a two-part hemispherical friction memberengaging each recess, means connecting corresponding portions of saidfriction members, said means comprising a link member hingedly connectedat its ends to the two parts of said friction member, and spring meansfor holding the hinged members in extended position.

2. In a spring-unit, an upper follower, a bottom follower, saidfollowers having opposed sockets curved in cross-section, a pair ofopposed quadsecond pair of opposed quadrant friction elements engagingsaid sockets and lapping past the firstnamed pair and frictionallyengaging the same, means pivotally connecting the members of each pairtogether, and spring means for resisting the turning of pairs offriction elements in said sockets.

3. In a friction spring-unit, an upper follower, a lower follower,friction mechanism between said followers, said mechanism comprising aplurality of pairs of segmental spheres, one of each pair engaging in asegmental spherical recess in one of said followers and the othersegmental spheres of the other pair engaging in a segmental recess inthe other follower, and means for movably connecting the members of eachpair together.

4. In a friction spring-unit, a bottom follower, a top follower,mechanism including compression springs between said followers forfrictionally resisting the compression of said unit, said mechanismcomprising members rotatable about axes extending transversely to thelongitudinal axis of the spring-unit having a frictional contact withsaid followers, and with each other.

5. In a friction spring-unit, a bottom follower, a top follower,mechanism including compression springs between said followers forfrictionally resisting the compression of said unit, said mechanismcomprising friction members arranged in pairs pivotally connectedtogether and rotatable in opposite directions when said unit iscompressed, said pairs frictionally engaging each other and frictionallyengaging the followers.

6. A friction spring-unit comprising top and bottom followers, saidfollowers having semispherical sockets facing each other, sectionalhemispherical friction elements engaging in said sockets, arms on saidelements extending diagonally outwardly, said elements being connectedin two pairs, one of each pair being above the other member of the pair,a link for connecting the members of each pair together, and a springbetween the members of each pair for yieldingly resisting the elementsof each pair from approaching each other when the unit is compressed.

7. A friction spring-unit comprising a top follower, a bottom follower,said followers having opposed sockets having friction surfaces curved incross-section, a pair of segmental spherical friction elements in eachsocket and rotatable in opposite directions when the unit is compressed,

means for movably connecting one of each pair of friction elementstogether, means for connecting the other of each pair of frictionelements together, said means causing rotation of said elements uponcompression of said unit, and springs between the elements connectedtogether for yieldingly resisting the rotation of said elements when theunit is compressed.

8. A friction spring-unit comprising upper and lower followers, frictionelements arranged in pairs pivotally connected together and rotatablyengaging said followers and one another, and resilient means foryieldingly resisting the compression of said unit and for forcing saidelements into frictional engagement with said followers and with oneanother.

9. In a friction spring-unit, a pair of opposed followers, two pairs offriction elements frictionally engaging said followers, means forconnecting the elements of one pair together, means for connecting theelements of the other pair toments of the other follower for forming twosets of friction elements, a spring between each set, and means forforcing the elements of each pair into frictional contact with oneanother when said unit is compressed.

11. In a friction spring-unit, an upper and a lower follower havingopposed hemispherical recesses therein, two spherical segments in eachrecess, the segments at one side of a vertical plane through saidrecesses constituting a pair of segments, the segments of each recesshaving contacting faces in a vertical plane, each segment having aninwardly and laterally extending arm, links for pivotally connecting thearms of each pair of segments together, a spring between each pair ofsegments, said springs being normally substantially vertical andadjacent to the vertical diameter of said recesses, whereby frictionbetween said segments will be increased as the unit is compressed.

12. In a friction spring-unit, an upper and a lower follower havingopposed hemispherical recesses therein, two spherical segments in eachrecess, the segments at one side of a vertical plane through saidrecesses constituting a pair of segments, the segments of each recesshaving contacting faces in a vertical plane, each segment having aninwardly and. laterally extending arm, links for pivotally connectingthe arms of each pair of segments together, a spring between each pairof segments, said springs being normally substantially vertical andadjacent to the vertical diameter of said recesses, and cooperatingmeans on said segments and followers for limiting the separation of saidfollowers.

13. A spring-unit for use in a bolster supporting spring assemblycomprising a cap member, a base member, said members having opposedhemispherical recesses, a two-part hemispherical friction memberengaging each recess, hinge means connecting corresponding portions ofsaid friction members, spring means for holding the hinged members inextended position, and a segmental flange extending about each recessfor engaging said friction members for limiting the compression of saidunit.

14. In a friction spring-unit, a bottom follower, a top follower,mechanism including compression springs between said followers forfrictionally resisting the compression of said unit, said mechanismcomprising rotatable members having a frictional contactwith'saidfollowers, and with

